Anterior fontanelle morphology in unilateral coronal synostosis: a clear clinical (nonradiographic) sign for the diagnosis of frontal plagiocephaly.

BACKGROUND: A review of patients with unilateral coronal synostosis treated at the Royal Children's Hospital was performed to explore the hypothesis that the clinically palpated shape of the anterior fontanelle in nonsyndromic unilateral coronal synostosis is triangular rather than the normal diamond shape.

METHODS: Three-dimensional computed tomographic scans were reviewed to assess the morphology of the anterior fontanelle. It is to be noted that these methods are purely for the purposes of describing the sign, and a three-dimensional computed tomographic scan is not required to elicit this clinical sign.

RESULTS: Twenty-eight patient records were identified, of which 18 had had three-dimensional computed tomographic scans. In eight of these, the anterior fontanelle was closed at the time of computed tomographic scanning, and in 10 it was open. Of the open fontanelles, all were triangular, supporting the hypothesis.

CONCLUSIONS: The shape of the fontanelle is an additional useful clinical sign with which to discriminate between synostotic plagiocephaly (triangular fontanelle) and deformational plagiocephaly (diamond-shaped fontanelle), along with those previously described by Mulliken and Huang. An algorithm is presented using these clinical indicators to both guide and minimize the use of radiology investigations.